2-phenyl-2-alkenals

ABSTRACT

NOVEL UNSATURATED ALDEHYDES, PARTICULARLY 2-PHENYL-2ALKENALS, USEFUL FOR PREPARING FLAVORING COMPOSITIONS AND FOOD COMPOSITIONS, PARTICULARLY THOSE HAVING CHOCOLATE OR COCOA FLAVOR AAND/OR AROMA QUALITIES, FLAVORING AND FOOD COMPOSITIONS CONTAINING SUCH ALDEHYDES, AND METHODS FOR PREPARING SUCH ALDEHYDES AND COMPOSITIONS.

United States Patent O Ser. No. 92,244

Int. Cl. C076 47/48 US. Cl. 260-599 6 Claims ABSTRACT OF THE DISCLOSURENovel unsaturated aldehydes, particularly 2-phenyl-2- alkenals, usefulfor preparing flavoring compositions and food compositions, particularlythose having chocolate or cocoa flavor and/or aroma qualities; flavoringand food compositions containing such aldehydes; and methods forpreparing such aldehydes and compositions.

This application is a division of application Ser. No. 724,611 filed onApr. 26, 1968, and now Pat. No. 3,582,360.

BACKGROUND OF THE INVENTION There is a need for materials which canimpart a desired flavor and/or aroma to foodstuffs or which can be usedto enhance or alter the naturally occurring flavors in foodstuffs.Chocolateand cocoa-flavored foodstuffs are very popular, and a greatdeal of effort has gone into the preparation of materials which have anatural chocolate or cocoa flavor and into efforts to improve thechocolate and cocoa flavors of certain types of natural materials.

In the past, it was found that substitute chocolate and cocoa flavoringmaterials lacked certain flavor and aroma characteristics found inquality chocolate and cocoa, and the products made from such materialswere deficient in such characteristics.

THE INVENTION The invention comprises the novel compositions andcomponent mixtures comprised in such compositions, as well as the novelprocesses and steps of processes according to which such compositionsmay be manufactured, specific embodiments of which are describedhereinafter by way of example only and in accordance with what is nowconsidered to be the preferred manner of practicing the invention.

Briefly, this invention provides 2-phenyl-2-alkenals capable ofimparting chocolate and/ or cocoa flavor and/ or aroma or of enhancingsuch flavor and aroma. The present invention also provides flavoringcompositions and food compositions containing small quantities of suchZ-phenyl-Z-alkenals effective to impart a chocolate and/or cocoa flavorand/or fragrance quality to, or enhance such quality in, suchcompositions.

Many chocolate and cocoa foods and flavoring materials lack a certainflavor and aroma note, and this lack substantially detracts from theiroverall organoleptic impression. It has been found that this missingflavor note is one which can be characterized as green pungentcocoalike. This green pungent cocoa-like flavor and aroma note issupplied to chocolate, cocoa and other flavors according to the presentinvention by the addition of unsaturated aldehydes, more specifically2-phenyl-2-alkenals having the structure 3,754,038 Patented Aug. 21,1973 These unsaturated aldehydes can be cis, trans, or mix tures of thetwo isomers, and the foregoing formula is intended to represent suchisomers. It will be understood that in general the alkenal isalkyl-substituted and the phenyl group substituent on the a-carbon atomcan be unsubstituted or monoor dialkyl-substituted, so that R in theforegoing formula is an alkyl group containing from 3 or 4 carbon atoms,and R and R are hydrogen or lower alkyl having from one to about threecarbon atoms.

The particular interesting green pungent cocoa-like flavor is present ina greater degree as the number of carbon atoms in the propenal chainincreases. It will be understood from this description that the alkylgroups can comprise primary and secondary carbon atoms. Thus, R can forexample be methyl, ethyl, isopropyl, isobutyl, or secondary butyl.

Substitution of the phenyl ring has the effect of varying the flavorcharacter of the propenals of this invention. Generally as the chainlength of one of the alkyl groups on the phenyl ring increases, theothers should be shorter. Some of the more preferred alkenals accordingto this invention are monoalkyl-substituted on the phenyl ring. It willbe understood that the alkyl group substituent on the phenyl ring can bestraightor branched-chain. Thus, R and R can be methyl, ethyl, orisopropyl and can be the same or different. In certain aspects of thisinvention, it is greatly preferred that R and R both be methyl or that Rbe methyl, ethyl, or isopropyl and R, be hydrogen.

In many instances the optimum balance of flavor and/ or aroma isobtained by utilizing a mixture of the 2- phenyl-Z-alkenals. Whenmixtures of aldehydes are used, their proportions can be varied to suitthe particular composition which is to be flavored, enhanced, orotherwise altered and will depend upon whether the invention is beingutilized to enhance the flavor of a chocolate, cocoa, or other foodstuffwhich already has some desirable flavor and aroma characteristics orwhether the entire flavor and/or aroma are to be supplied by theaddition of a flavoring composition. For example, it has been found whenpreparing cocoa flavors that a good blend is obtained by using a mixtureof about -90% of S-methyl- 2-phenyl-2-hexenal, about 37% of4-methyl-2-phenyl-2- pentenal and from about 37% of 2-phenyl-2-butenal.It will be understood that these ratios can be varied as necessary toenhance or fortify the flavor of the foodstuff. All parts, proportions,percentages and ratios herein are by weight, unless otherwise indicated.

It will be appreciated from the foregoing that the aldehydes accordingto this invention can be mixed with other flavoring ingredients,carriers, and vehicles to form compositions suitable for imparting aflavor to, enhancing the flavor in, or altering the flavor of, acomestible. Such compositions are herein called flavoring compositions.The aldehydes according to this invention can also be added directly toa food composition to alter, enhance, modify or impart flavor to thefood composition. In the latter instance it is only necessary to add thealdehyde or aldehydes and to make certain that they are thoroughly anduniformly distributed through the food.

When the aldehydes of this invention are used in flavoring compositionsto enhance existing flavors in, or to provide the entire flavorimpression to, a foodstuff, the aldehydes can be combined with organicacids including fatty, saturated, unsaturated and amino acids, alcoholsincluding primary and secondary alcohols, esters, carbonyl compoundsincluding aldehydes and ketones, lactones, cyclic organic materialsincluding benzene derivatives, alicyclics, heterocyclics such as furans,pyridines, pyrazines and the like, sulfur-containing materials includingthiols, sulfides, disulfides and the like, proteins, lipids,carbohydrates, and so-called flavor potentiators such as monosodiumglutamate, guanylates, inosinates, natural flavoring materials such ascocoa, vanilla, artificial flavoring materials such as vanillin, and thelike. It will be appreciated that the types and amounts of materialsselected from the foregoing groups of materials will depend upon theprecise organoleptic character desired in the finished product and,especially in the case of flavoring compositions used to enhance otherflavors, will vary according to the foodstuff to which flavor and aromaare to be imparted. Inorganic materials such as sodium chloride andfreshness preservers such as butylated hydroxyanisole and propyl gallatecan be added for their adjuvant or preservative effects on the flavoringcomposition.

As noted above, it can also be desirable to utilize carriers such as gumarabic and carrageenen or vehicles such as ethyl alcohol, water,propylene glycol. When the carrier is an emulsion, the flavoringcomposition can also contain emulsifiers such as monoand diglycerides offatty acids and the like. With these carriers or vehicles the desiredphysical form of the composition can be prepared. It will be understoodthat the aldehydes of this invention can be used in spray-dried, liquid,encapsulated, emulsified and other forms in which flavorings are addedto foodstuffs. The aldehydes can be so used alone or in combination withthe other ingredients set forth herein. In the case of a foodstuff whichis prepared from a combination of ingredients the aldehydes, flavorenhancers and flavoring compositions of this invention can be added toone of the ingredients and thereby be incorporated into the compositionas a whole.

The amount of 2-phenyl-2-alkenal or -alkenals used should be suflicientto impart a green pungent cocoa flavor and aroma note to the ultimatefoodstuff in which the aldehydes are used. Thus, a small but effectiveamount of aldehyde sufficient to provide a green pungent cocoa flavornote to round out the cococa, chocolate, or other flavor note in theultimate foodstuff is used. The amount used will vary depending upon theultimate food composition to be flavored; for example, more may berequired in providing a full, rounded chocolate flavor to an unflavoredmaterial and less may be required when this invention is used to enhancea chocolate or cocoa food stuff or flavoring material which is deficientin natural flavor or aroma.

Those skilled in the art will appreciate that the amount of aldehydeaccording to this invention can be varied over a range to provide thedesired flavor and aroma. The use of too little of the aldehyde oraldehydes will not give the full benefit, while too much aldehyde willmake the flavor compositions and foodstuffs needless costly, and inextreme cases will unbalance the flavor and aroma so that optimumresults are not obtained.

It is accordingly preferred that the ultimate food composition containat least about parts per million (p.p.m.) of the aldehydes, based ontotal composition, and it is not generally desirable to use more thanabout 500 ppm. in the finished composition. Accordingly, the desirablerange for use in the practice of this invention is from about 10 toabout 50 ppm. of the Z-phenyl-Z-alkenal compound or compounds. Whenthese aldehydes are added to the foodstuff in the form of chocolate,cocoa, or other flavor composition, the amount should be sufficient toimpart the requisite flavor and/ or aroma note to the composition sothat the flavor and aroma will be balanced in the finished foodstuff.Accordingly, the flavoring compositions of this invention preferablycontain from about .02% to about 10% of 2-phenyl-2-alkenal based on thetotal weight of said flavoring composition.

The aldehydes according to this invention are added to the foodstuffeither alone or as flavor compositions formed by admixture of suchaldehydes with conventional chocolate, cocoa, or other heavy flavor andaroma ingredients such as amyl phenyl acetate, vanillin, n-butylphenylethyl acetal, and diacetyl. These can be combined in proportionsnormally used in the art for preparation of the flavor. For example, thefollowing composition can be prepared:

Ingredient: Amount (oz. av.) Amylphenyl acetate 4.000 Vanillin 4.000Aldehyde C 18 0.125 Vera-traldehyde 0.125 n-Butylphenyl ethylacetal0.500 Propylene glycol 48.250 Diacetyl g 0.5005-methyl-2-phenyl-Z-hexenal 0.500

When the aldehydes according to this invention are used in theformulation of chocolate flavoring material, it has been foundespecially useful to combine them with a vanilla flavoring agent and analkyl acetate. Thus, the aldehydes can be combined with vanilla extractor other vanilla flavoring agent such as vanillin and with amyl phenylacetate. Compositions containing an aldehyde or aldehydes according tothis invention with vanillin and the amyl phenyl acetate provide aflavor enhancer which imparts a more natural cocoa flavor and aroma toimitation cocoa flavor compositions.

The flavoring compositions of this invention can be added to thefoodstuffs by conventional methods known in the art. For example, in thepreparation of a chocolate frosting mix, the flavoring compositions canbe incorporated with the fat, sugar, thickeners, freshness preserversand the like, and admixed in a conventional blender to obtain thedesired consistency. Alternatively, the flavor material of thisinvention, together with any other liquids if desired, can be admixedwith a carrier, such as gum arable, gum tragacanth, carrageenen and thelike, and spray-dried to obtain a particulate solid flavoring material.

Where a powdered prepared cocoa mix is being made, the dried milksolids, sugar and flavoring compositions or unsaturated aldehydes ofthis invention are mixed together in a dry blender to attain uniformity.In the case of such prepared dry mixes, the aldehydes or flavorcompositions of the present invention can be distributed on one or moreof the solid ingredients or any portion thereof, for example, the driedmilk solids, and subsequently blended with the other ingredients.

When liquid materials are involved in the preparation of foodstuffs, forexample, cake batters and chocolate milk, the flavoring materials ofthis invention can be combined with either the liquid to be used in thefinished composition, or alternatively they can be added with a liquidcarrier in which they are dissolved, emulsified, or otherwise dispersed.

In adding the aldehydes of this invention to a foodstuff or flavorcomposition, it will be understood that the aldehyde or aldehydes can beadded in the form of precursors which will release the free aldehydicmaterial upon hydrolysis, heating, or other treatment to which thefoodstuff or a component thereof is subjected. Thus, when hydrolyticconditions will obtain prior to use, the aldehyde or aldehydes can beadded in the form of the corresponding acetals such as the lower dialkylacetal or hemiacetal, a bisulflte addition compound, and the like. Suchmodes of addition are contemplated within the purview of this inventionand are regarded as equivalent to adding the aldehyde or aldehydes perse.

The novel materials of this invention can be prepared by reaction of twoaldehydes in the presence of a basic catalyst via the aldol condensationreaction:

wherein R R and R are as defined above.

In carrying out the foregoing reaction phenylacetaldehyde or asubstituted phenyl acetaldehyde, e.g., isopropyl phenyl acetaldehyde, isreacted with a lower alkyl aldehyde having two or more carbon atoms inthe molecule. Thus, the aromatic acetaldehyde can be reacted withacetaldehyde, propionaldehyde, butyraldehyde, and branched lower alkylaldehydes such as isovaleraldehyde and the like. It is preferred to usesubstantially equimolar proportions of the aldehydes, since in manyinstances a substantial excess of either aldehyde will unnecessarilyconsume the reactants in the production of undesired by-products.

The reaction is preferably carried out in the presence of a vehicleinert to the reactants under the reaction conditions. Examples of inertsolvents which can be used in practicing the invention are ethylalcohol, propanol, and the like. Such inert vehicles permit moreaccurate control of the temperature and rate of the reaction anddiminish the quantity of undesired by-products.

The reaction to produce the aldehydes of this invention is preferablycarried out in the presence of a basic catalyst. The catalyst shouldpreferably be soluble in the reaction medium formed by the inertvehicle, if any, and the reactant aldehydes. Convenient basic catalystsare the alkali metal and alkaline earth metal hydroxides such as sodiumhydroxide, potassium hydroxide, lithium hydroxide, barium hydroxide,calcium hydroxide and magnesium hydroxide, and the salts of strong basesand weaker acids such as sodium propionate, sodium acetate, potassiumacetate, and the like. The alkali metal acetates and hydroxides aregenerally preferred in carrying out the process to produce the alkenalsof this invention. It will be appreciated by those skilled in the artthat an excess of strong base can produce undesirable by-products.

The temperature at which the reaction is carried out can vary over awide range depending upon the particular reactant aldehydes, the basiccatalyst, and the vehicle. Generally, low temperatures involve longreaction times, whereas very high temperatures require high-pressurevessels and may produce undesired by-products. -It is accordinglypreferred to carry out the process at temperatures in the range of fromabout 60 to about 150 C., and it is most convenient to carry out thereaction at the reflux temperature of the reaction mixture.

It will be appreciated by those skilled in the art that the reaction canbe carried out at subor super-atmospheric pressures depending upon thereactants, solvents, catalysts, and reaction times. It is generallypreferred to carry out the reaction under atmospheric pressure, and theinert vehicle can be chosen to provide the desired reaction rate at itsreflux temperature.

The time of the reaction can be varied over a wide range of from one tothirty hours depending upon the reactants, the completeness desired, andthe tendency toward production of undesired by-products.

After the reaction is completed to the desired extent, the product canbe isolated from the reaction mixtures by convenient means such asextraction, distillation, and an inert solution such as sodium chlorideand dried to remove the basic catalyst and can then be washed with thelike. The product is washed or treated with acid to remove any traces ofwater remaining in the organic phase. The product can be separated fromthe dried mixture by convenient methods such as distillation, extractionand the like. Since minor amounts of undesired aldol condensates can beformed in addition to the desired aldehydes, the reaction product ispreferably purified by fractional distillation. When the2-phenyl-2-alkenal or -alkenals so produced is or are to be used inpreparing flavor compositions or food compositions as described herein,there should be not impurities present which would contribute a foreignflavor or off-flavor or aroma.

The following examples are given to illustrate embodiments of theinvention as it is now preferred to practice it. It will be understoodthat these examples are illustrative, and the invention is not to beconsidered as restricted thereto except as indicated in the appendedclaims.

Example I.-Preparation of 5-methyl-Z-phenyl-Z-hexenal Into a five-literMorton flask, equipped with stirrer, thermometer, heating mantle, refluxcondenser and addition tube the following ingredients are introduced:

G. Anhydrous sodium acetate (2.3 moles) 186 Water 370 Anhydrous ethylalcohol 370 The solution is maintained at 25 C. and stirred until thesodium acetate completely dissolves. The following ingredients are addedthrough a dropping funnel during a 15-minute period:

G. Phenylacetaldehyde (3.7 moles) 440 Isovaleraldehyde (3.7 moles) 318The solution is heated to reflux and maintained there for about threehours. The reaction progress is monitored using a gas-liquidchromatographic (GLC) technique. (Conditions: Column T=200 0; flow rate,m1./ min.; A" x 8' column packed with Chromosorb W 60/80 mesh, adiatomaceous earth sold by Johns Manville Company coated with SiliconeSE-30 gum rubber silicone.)

When the reaction is completed, the reaction mass exists in two phases:an aqueous phase and an organic non-aqueous phase. The aqueous phase isseparated from the organic phase, and the aqueous phase is washed withtwo 500 ml. volumes of diethyl ether. The ether washings are combinedwith the organic phase, and the organic phase is then Washed in iceWater until the final washing has a pH of 7. The organic phase is thenwashed with a saturated NaCl solution and dried over anhydrous magnesiumsulfate. The dried organic phase is fractionally distilled at a 1:1reflux ratio.

The desired 5-methyl-2-phenyl 2 -hexenal distills at a 1:1 reflux ratio.

The desired 5-'methyl-2-phenyl-2-hexenal distills at 96- C. at about 0.7mm. Hg pressure in a yield of IR (infrared)analysis of the desiredproduct yields the following data:

Wave number (cm.- Interpretation 2700, 2800, 1630,1675 Conjugatedaldehyde. 700, 725 Monosubstituted benzene.

NMR (nuclear magnetic resonance) analysis yields the following data:

P .p.m. (1') 9.12 ((1, J=6.0 Hz., 6H)

Interpretation i CHa-[C- CH3 7.80 (t, 2H) =CHCH2(|JH-CH3 8.3 (m, 1H) CH37 Example II.Preparation of 4-methyl-2-phenyl-2- pentenal Into athree-liter Morton three-neck flask, equipped with stirrer, thermometer,heating mantle, reflux condenser and addition tube the followingingredients are introduced:

G. Anhydrous sodium acetate (2.3 moles) 186 50% ethyl alcohol 740Phenylacetaldehyde (3.7 moles) 440 Isobutyraldehyde (4.2 moles) 305 Thesolution is heated to reflux and maintained there for a period of aboutfour hours. The reaction progress is monitored using a GLC technique.(Conditions: Column T=200 C.; flow rate, 100 ml./min.; A" x 8' columnpacked with Chromosorb W 60/80 mesh coated with Silicone SE-30.)

When the reaction is completed, the reaction mass exists in two phases:an aqueous phase and an organic phase. The aqueous phase is separatedfrom the organic phase, and the aqueous phase is washed with two 220 ml.volumes of diethyl ether. The ether washings are combined with theorganic phase, and the organic phase is then washed successively with500 ml. 20% HCl, 500 ml. saturated NaI-ICOg and 500 ml. saturated NaClsolution. The layer is then dried over anhydrous sodium sulfate. Thedried organic layer is fractionally distilled at a 4:1 reflux ratio.

The desired 4-rnethy1-2-phenyl-2-pentenal distills at 82- 87 C. at about0.7 mm. Hg pressure in a yield of 174.1 g.

IR analysis of the desired product yields the following data:

Wave number (cmr Interpretation 2.700, 2800, 1630, 1675 Conjugatedaldehyde. 708, 725 M-onosubstituted benzene.

NMR analysis yields the following data:

Mass spectral analysis shows the following peaks in order of decreasingintensity: 1714 (M'*), 103, 131, 91, 159.

Example III.--Preparation of 2-phenyl-2-butenal Into a two-liter Mortonthree-neck flask, equipped with stirrer, thermometer, heating mantle,and reflux condenser the following ingredients are introduced:

G. Anhydrous sodium acetate (2.3 moles) 186 Water 370 Anhydrous ethylalcohol 370 Phenylacetaldehyde (3.7 moles) 440 Acetaldehyde (4.23 moles)186 The solution is heated to reflux and maintained there for a periodof about 24 hours, The reaction process is monitored using a GLCtechnique. (Conditions: Column T=200 C.; flow rate, 100 ml./min.; A" x 8column packed with Chromosorb W 60/80 mesh coated with Silicone SIB-30).

When the reaction is completed, the reaction mass exists in two phases:an anneous phase and an organic non- Wave number (cmr Interpretation2700, 2800, 1630, 1680 Conjugated aldehyde.

700, 730 Monosubstituted benzene.

NMR analysis yields the following data:

P.p.m. (1') Interpretation 8.12 (d, .T=7.2 Hz.,3H) CH3CH= 3.55 ((1,111)ore-0B 2.77 (m, 511).. Aryl protons;

Mass spectral analysis shows the following peaks in; in order ofdecreasing intensity: 117, 146(M+), 115, 91, 116.

Example IV.Preparation of 4-methyl-2-phenylhexenal Into a five-literMorton flask, equipped with stirrer,

thermometer, heating mantle, reflux condenser and addition tube thefollowing ingredients are introduced:

G. Anhydrous sodium acetate (2.3 moles) 186 Water 370 Anhydrous ethylalcohol 370 The solution is maintained at 25 C. and stirred until thesodium acetate completely dissolves. A mixture of the followingingredients is added through a dropping funnel during a IS-minnteperiod:

G. Phenylacetaldehyde (3.7 moles) 440 Z-methyl'butyraldehyde (4.2 moles)365 The addition of this mixture causes the temperature of the reactionmass to rise to 35 C.

The solution is heated to reflux and maintained there for a period ofabout nine hours. The reaction progress is monitored using gas-liquidchromatography (GLC) technique. (Conditions: Column T=200 C.; Flow rate,ml./min.; 1 x 8' column packed with Chromosorb W 60/80 mesh coated withSilicone SE-30). Ten g. of Na CO is then added, and the reaction mass isstirred for a period of two hours. Five g. of KOH is added, and thereaction mass is stirred at reflux Eat a period of 12. hours at whichtime GLC indicates substantial diminution of the phenyl acetaldehydereactant.

When the reaction is completed, the reaction mass exists in two phases:an aqueous phase and an organic phase. The aqueous phase is separatedfrom the organic phase, and the aqueous phase is Washed with two ml.volumes of diethyl ether. The ether washings are combined with theorganic phase and the organic phase is then Washed successively with 500ml. 15% HCl solution; 500 ml. saturated NaCl; 500 ml. 5% sodiumbicarbonate; and two 500 ml. portions of saturated NaCl solution. Thewashed organic phase is dried over anhydrous magnesium sulfate andfractionally distilled at a 5:1 reflux ratio.

The desired 4 methyl-2-phenyl-2-hexena1 distills at 88- 98 C. at about0.8-1.0 mm. Hg pressure. 7

IR analysis of the desired product yields the following data:

Wave number (cmr Interpretation 2720, 2900, 1630, 1765 Conjugatedaldehyde. 700, 725 Monosubstituted benzene. 1370 Methyl.

NMR analysis yields the following data:

Mass spectral analysis shows the following peaks, in order of decreasingintensity: 91, 188 (M+), 103, 131, 159.

Example V.Preparation of S-methyI-Z-(dimethylphenyl) -2-hexenal Into a25 m1. round-bottom flask equipped with a reflux condenser are added thefollowing ingredients:

Distilled Water 0.50 95% Ethyl alcohol 1.10 Sodium acetate trihydrate0.80

The contents of the flask are warmed slightly until the sodium acetatedissolves. The following mixture of 1ngredients is then added:

G. Dimethylphenylacetaldehyde (0.01 mole) 1.48 Isovaleraldehyde (0.01mole) 0.86

The dimethylphenylacetaldehyde is a mixture of the dimethylphenylisomers.

The flask is heated in a boiling water bath and stirred magnetically. A20 mg. portion of potassium hydroxide pellets is added and the mixtureis refluxed for three hours. The reaction is monitored by GLC.(Conditions: F & M 700 Carbowax 20-M packed column, 8 x A O.D., flowrate 100 m1./min., temperature programmed 100-225 C., 4 C./min.)

After the reaction is judged to be completed, the organic layer isseparated from the aqueous layer and dried over anhydrous sodiumsulfate. The products are then purified by preparative gaschromatography.

The products isolated and identified are -methyl-2-(2,6-dimethylphenyl)-2-hexenal and 5-methy1-2-(2,4-dimethylphenyl)-2-hexenal containing some 5-methyl-2-(3,5-dirnethylphenyl)-2-hexenal. Each of these products can be used tocontribute to a desired cocoa flavor.

Example VI.Preparation of 5-methy1-2-(isopropylphenyl) -2-hexenal Analdol condensation of isopropylphenylacetaldehyde (homocuminic aldehyde)with isovaleraldehyde is con-- ducted according to the procedure givenabove. GLC analysis shows. the production of5-methyl-2-(2-isopropylphenyl)-2-hexenal,5methyl-2-(3-isopropylphenyl)-2- hexenal, and5-methyl-2-(4-isopropylphenyl)-2-hexenal.

Evaluation of a mixture containing 43% of the 2- isopropylphenyl isomer,46% of the 3-isopropylphenyl isomer, and 11% of the 4-isopropylphenylisomer shows a cocoa-like odor and a slightly bitter taste. Similarevaluation of a mixture of 9% 2-, 45% 3- and 46% 4- isopropylphenylcompounds and pure 4-isopropylphenyl shows, respectively, a cocoa-likeodor and a heavy cocoa-like taste and a cocoa odor and cocoa tastenuance.

5-methyl-2-(4-methylphenyl) 2 hexenal is similarly prepared bybase-catalyzed aldol condensation of pmethylphenylacetaldehyde withisovaleraldehyde. This material has a cocoa-like flavor note suitablefor the preparation of cocoa and chocolate flavors.

Example VII The following base cocoa flavor material is prepared byadmixing the following ingredients:

Ingredient: Parts by weight Vanillin 60.0 Amylphenyl acetate 45.0 Benzylbutyrate 2.5 Veratraldeh'yde 2.5 Maltol 1.0 Propylene glycol 530.0

To 1 g. of this base cocoa flavor, 50 mg. of 5-methyl-2-phenyl-Z-hexenal is added. This hexenal addition alters the imitationcocoa flavor to provide a more natural cocoa flavor and impart acharacter of bitter chocolate.

Example VIII To 1 g. of the base cocoa flavor described in Example VII,50 mg. of a mixture of 2-phenyl-2-alkenals is added. The composition ofthe mixture is:

Ingredient: Parts by Weight 2-phenyl-2-butenal 4.04-methyl-2-phenyl-2-pentenal 1.5 5-methyl-2-phenyl-2-hexenal 38.0

This aldehyde mixture alters the imitation flavor to provide anexcellent flavor with a strong chocolate character.

Example IX The aldehyde mixture described in Example VII is added to acommercially available soluble powdered cocoa beverage to provide p.p.m.of the added aldehydes. The flavor is enhanced to provide a high qualitychocolate drink.

Example X wherein R and R are hydrogen or lower alkyl having from one toabout three carbon atoms, and when R and R are both hydrogen then R ispropyl or methylisopropyl and when at least one of R and R is said loweralkyl then R is an alkyl group having three or four carbon atoms, saidalkenal being apart from the natural constituents of cocoa beans.

11 12 2. An aikenal according to claim 1, wherein R is 6. An alkenalaccording to claim 1, wherein R is propyl and R and R are hydrogen.isobutyl, R is isopropyl, and R is hydrogen.

3. An alkenal according to claim 1, wherein R is methylisopropyl and Rand R are hydrogen. References Cited A11 alkellal according to claimwherein 1 is 5 Van Praag et a1.: Jour. Agr. & Food Chem, Vol. 16,isobutyl and R and R are methyl. No. 6 (1968), 1005-1008.

5. An aikenal according to claim 1, wherein R is isobutyl, R is methyl,and R is hydrogen. BERNARD HELFIN, Primary Examiner UNITED STATES PATENTOFFICE CERTIFICATE OF CORREfiTION Patent No. 3,?5Q ,Ol Dat Amgust 2.1,1971 lnventofls) Michel Van Praag, et al.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 3', line 59, "5O should read 500 Column 5, lines 58-60, shouldread the like. The product is washed or treated with acid to remove thebasic catalyst and can then be washed with an inert solution such assodium chloride and dried to Column 5, line 70, not should read noColumn 6, lines BS-and 39 should be deleted;

Column 6, lines 55-60, hydrogen atoms, "H, in the tabulation should beunderscored as shown.

P.p.m. (-r) Interpretation 9.12 (d, I==8.0 Hz., 6H) H cm-d-cm 55 l mo(c, 211) =cK-cg,-cH-om 8.3 (m, 1H) CH; 60 GHQ-Cg 3.41 (t, J=7.2 Hz.,1H)....-; =CE-CH: 2.80 (m, 5H) C-Ar 65 0.43 (3,13) ..I H

FORM PO-IOSO (10-69) USCOMM-DC 60376-P69 r us. sovskm lzur fugNTINGOFFICE: I969 0-366-334.

UNI ED STATES PATENT OFFICE P g 2 CERTIFICATE OF CORRECTION Patent No.3,75LT,038 Dated Augu ta, 973

lnventofls) Michel Van Praag, et al.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as. shown below:

Column 6, line 69, "1:" should read q Column 6, line 71 "118" shouldread 18,8

Column 7, lines O-5O, hydrogen atoms, "H" should be underscored asshown.

Column 7,- line 55, "171E" should read 17E Column 8, lines 18-22, thehydrogen atoms "H", should be underscored as shown:

l P.p.m."(-r) Interpretation 8.12 1-7.2 35-33)...- 7 HI- 3.56 2%. 1 2.7731,53) Aryl pro a 0.50 (s, 1H) m. ll

T-ORM PO-1050 (10-69) USCOMM-DC 60376-P69 u.s. GOVERNMENT PRINTINGOFFICE I969 O-356-384.

a UNITED STATES PATENT OFFICE Page 3 CERTIFICATE OF CORRECTION PatentNo. 3,75 h 3 Dated August 73 Inventor(S)MiChel Van Praag, et l It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 8, line 23, delete "in;

Column 8, line 27, after phenyl" insert 2 Column 9, lines 5-20, thehydrogen atoms "H", should be underscored as shown.

Signed and sealed this 2nd day of April 197M.

( SEAL) Attest:

EDWARD M .FLETCHER JR C MARSHALL DANN Attesting Officer 7 Commissionerof Patents ORM PO-1050 (10-69) USCOMM-DC 603764 69 [1.5. GOVERNMENTPRINTING OFFICE: I969 0-366-334. &

